SSL's are VERY cheap. There is no reason for any e-commerce site not to have it.
If a site has prices that seem too cheap and they don't have all the security badges and certifications like the larger sites- which may cost a bit more, don't buy from them.
When I smoked, there's no chance I'd try to buy crazy cheap cigarettes from Russia, yet it seems vapers will do anything- even compromise credit cards, to save a buck. The dirt cheap sites are probably saving money on credit card processing and security.